What can you add to egg whites make them more stable other than cream of tartar?

You're right, cream of tartar is a common ingredient for stabilizing egg whites, but there are a few other options you can use:

Acidic Ingredients:

* Lemon juice: A few drops of lemon juice will do the trick. It works just like cream of tartar by lowering the pH of the egg whites.

* Vinegar: White vinegar can be used as a substitute for cream of tartar. Use a similar amount to what you would use cream of tartar.

* Citric Acid: Citric acid powder is a great option for stabilizing egg whites. You'll need a tiny amount, about 1/8 teaspoon for 2 egg whites.

Other Methods:

* Salt: A pinch of salt can actually help to stabilize egg whites, although it won't create as stiff peaks as an acidic ingredient.

* Sugar: Adding sugar gradually while whipping can actually help stabilize egg whites. The sugar helps to bind the protein and makes the foam more stable. However, this method is better for recipes where you're adding sugar anyway, like meringues.

Important Tips:

* Clean Equipment: Make sure your mixing bowl and beaters are completely clean and free of grease. Any traces of fat will prevent the egg whites from whipping properly.

* Room Temperature Eggs: Egg whites whip best at room temperature.

* Whipping Speed: Start with a low speed and gradually increase as the egg whites become foamy.

No matter what you choose to use, remember that the goal is to lower the pH of the egg whites. This will help the proteins to unfold and bind together more effectively, creating a stable foam.